The eating habits of Diplodocus, one of the longest known dinosaur - about 30 meters in length and weighing around 15 tonnes, have been revealed by scientists using CT scans and biomechanical modelling.

There has been great debate about how Diplodocus, which lived around 150 million years ago, ate those large quantities of plants since its discovery over 130 years ago. To find out the answer, a team of international researchers, led by the University of Bristol and the Natural History Museum, used data from a CT scan and created a 3D model of a complete Diplodocus skull.

With the help of finite element analysis (FEA) — an imaging technology used in designing aeroplanes to orthopaedic implants, the model was analysed and digitally tested.

Paleontologist Mark Young at the University of Edinburgh and co-authors revealed the stresses on the dinosaur skull from three different eating behaviours: a normal bite, branch stripping and bark stripping.

The CT scans showed Diplodocus' skull received stress around the teeth and below the eye socket during normal vertical biting and stripping leaves from branches. However this stress wasn't enough to be unsafe for the bone.

The team says the teeth were used to grip rather than shear through vegetation, which would then be detached from the plant by pulling away or rotating the head, like a modern-day giraffe for instance.

The bark stripping scenario, however, produced much more stress in the same areas, especially around the teeth. These bones would not have been able to withstand the forces applied when stripping bark from trees.

The CT scan data also shows how many replacement teeth are behind each tooth, usually four," Young said. "These animals would have been constantly replacing teeth, possibly as frequently as every month."

The study was published in Naturwissenschaften, a natural sciences journal.